> I am not sure if I understand your question right. You want to replace
> ewvery a b by d. But what do you mean by "This replacement is required
> to work for arbitrary a and b".
This simply means that a and b actually stand for more complex
expressions involving trigonometric functions...
> Well, for the part that I understood:
>
> You have 4 different cases: a b, a b^n, a^n b, a^n b^m
> The rule for the first case is simply: a b -> d
> second case: a b^n_ -> b^(n-1) d
> third: a^n b -> a^(n-1) d
> four: a^n b^m -> a^Max[0, n - m] b^Max[0, m - n] d^Min[m, n]
OK, this does the job, however I'll use the shorter rule suggested by
Roland... I've also tested this with the actual expressions instead of
a and b (see above) and it works fine.
Thanks,
Oliver